1 /*
   2  * Copyright (c) 1997, 2018, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 #ifndef SHARE_VM_CODE_CODECACHE_HPP
  26 #define SHARE_VM_CODE_CODECACHE_HPP
  27 
  28 #include "code/codeBlob.hpp"
  29 #include "code/nmethod.hpp"
  30 #include "gc/shared/gcBehaviours.hpp"
  31 #include "memory/allocation.hpp"
  32 #include "memory/heap.hpp"
  33 #include "oops/instanceKlass.hpp"
  34 #include "oops/oopsHierarchy.hpp"
  35 #include "runtime/mutexLocker.hpp"
  36 
  37 // The CodeCache implements the code cache for various pieces of generated
  38 // code, e.g., compiled java methods, runtime stubs, transition frames, etc.
  39 // The entries in the CodeCache are all CodeBlob's.
  40 
  41 // -- Implementation --
  42 // The CodeCache consists of one or more CodeHeaps, each of which contains
  43 // CodeBlobs of a specific CodeBlobType. Currently heaps for the following
  44 // types are available:
  45 //  - Non-nmethods: Non-nmethods like Buffers, Adapters and Runtime Stubs
  46 //  - Profiled nmethods: nmethods that are profiled, i.e., those
  47 //    executed at level 2 or 3
  48 //  - Non-Profiled nmethods: nmethods that are not profiled, i.e., those
  49 //    executed at level 1 or 4 and native methods
  50 //  - All: Used for code of all types if code cache segmentation is disabled.
  51 //
  52 // In the rare case of the non-nmethod code heap getting full, non-nmethod code
  53 // will be stored in the non-profiled code heap as a fallback solution.
  54 //
  55 // Depending on the availability of compilers and TieredCompilation there
  56 // may be fewer heaps. The size of the code heaps depends on the values of
  57 // ReservedCodeCacheSize, NonProfiledCodeHeapSize and ProfiledCodeHeapSize
  58 // (see CodeCache::heap_available(..) and CodeCache::initialize_heaps(..)
  59 // for details).
  60 //
  61 // Code cache segmentation is controlled by the flag SegmentedCodeCache.
  62 // If turned off, all code types are stored in a single code heap. By default
  63 // code cache segmentation is turned on if TieredCompilation is enabled and
  64 // ReservedCodeCacheSize >= 240 MB.
  65 //
  66 // All methods of the CodeCache accepting a CodeBlobType only apply to
  67 // CodeBlobs of the given type. For example, iteration over the
  68 // CodeBlobs of a specific type can be done by using CodeCache::first_blob(..)
  69 // and CodeCache::next_blob(..) and providing the corresponding CodeBlobType.
  70 //
  71 // IMPORTANT: If you add new CodeHeaps to the code cache or change the
  72 // existing ones, make sure to adapt the dtrace scripts (jhelper.d) for
  73 // Solaris and BSD.
  74 
  75 class ExceptionCache;
  76 class KlassDepChange;
  77 class OopClosure;
  78 class ShenandoahParallelCodeHeapIterator;
  79 
  80 class CodeCache : AllStatic {
  81   friend class VMStructs;
  82   friend class JVMCIVMStructs;
  83   template <class T, class Filter> friend class CodeBlobIterator;
  84   friend class WhiteBox;
  85   friend class CodeCacheLoader;
  86   friend class ShenandoahParallelCodeHeapIterator;
  87  private:
  88   // CodeHeaps of the cache
  89   static GrowableArray<CodeHeap*>* _heaps;
  90   static GrowableArray<CodeHeap*>* _compiled_heaps;
  91   static GrowableArray<CodeHeap*>* _nmethod_heaps;
  92   static GrowableArray<CodeHeap*>* _allocable_heaps;
  93 
  94   static address _low_bound;                            // Lower bound of CodeHeap addresses
  95   static address _high_bound;                           // Upper bound of CodeHeap addresses
  96   static int _number_of_nmethods_with_dependencies;     // Total number of nmethods with dependencies
  97   static nmethod* _scavenge_root_nmethods;              // linked via nm->scavenge_root_link()
  98   static uint8_t _unloading_cycle;                      // Global state for recognizing old nmethods that need to be unloaded
  99 
 100   static ExceptionCache* volatile _exception_cache_purge_list;
 101 
 102   static void mark_scavenge_root_nmethods() PRODUCT_RETURN;
 103   static void verify_perm_nmethods(CodeBlobClosure* f_or_null) PRODUCT_RETURN;
 104 
 105   // CodeHeap management
 106   static void initialize_heaps();                             // Initializes the CodeHeaps
 107   // Check the code heap sizes set by the user via command line
 108   static void check_heap_sizes(size_t non_nmethod_size, size_t profiled_size, size_t non_profiled_size, size_t cache_size, bool all_set);
 109   // Creates a new heap with the given name and size, containing CodeBlobs of the given type
 110   static void add_heap(ReservedSpace rs, const char* name, int code_blob_type);
 111   static CodeHeap* get_code_heap_containing(void* p);         // Returns the CodeHeap containing the given pointer, or NULL
 112   static CodeHeap* get_code_heap(const CodeBlob* cb);         // Returns the CodeHeap for the given CodeBlob
 113   static CodeHeap* get_code_heap(int code_blob_type);         // Returns the CodeHeap for the given CodeBlobType
 114   // Returns the name of the VM option to set the size of the corresponding CodeHeap
 115   static const char* get_code_heap_flag_name(int code_blob_type);
 116   static size_t page_size(bool aligned = true);               // Returns the page size used by the CodeCache
 117   static ReservedCodeSpace reserve_heap_memory(size_t size);  // Reserves one continuous chunk of memory for the CodeHeaps
 118 
 119   // Iteration
 120   static CodeBlob* first_blob(CodeHeap* heap);                // Returns the first CodeBlob on the given CodeHeap
 121   static CodeBlob* first_blob(int code_blob_type);            // Returns the first CodeBlob of the given type
 122   static CodeBlob* next_blob(CodeHeap* heap, CodeBlob* cb);   // Returns the next CodeBlob on the given CodeHeap
 123 
 124   static size_t bytes_allocated_in_freelists();
 125   static int    allocated_segments();
 126   static size_t freelists_length();
 127 
 128   static void set_scavenge_root_nmethods(nmethod* nm) { _scavenge_root_nmethods = nm; }
 129   static void prune_scavenge_root_nmethods();
 130   static void unlink_scavenge_root_nmethod(nmethod* nm, nmethod* prev);
 131 
 132   // Make private to prevent unsafe calls.  Not all CodeBlob*'s are embedded in a CodeHeap.
 133   static bool contains(CodeBlob *p) { fatal("don't call me!"); return false; }
 134 
 135  public:
 136   // Initialization
 137   static void initialize();
 138 
 139   static int code_heap_compare(CodeHeap* const &lhs, CodeHeap* const &rhs);
 140 
 141   static void add_heap(CodeHeap* heap);
 142   static const GrowableArray<CodeHeap*>* heaps() { return _heaps; }
 143   static const GrowableArray<CodeHeap*>* compiled_heaps() { return _compiled_heaps; }
 144   static const GrowableArray<CodeHeap*>* nmethod_heaps() { return _nmethod_heaps; }
 145 
 146   // Allocation/administration
 147   static CodeBlob* allocate(int size, int code_blob_type, int orig_code_blob_type = CodeBlobType::All); // allocates a new CodeBlob
 148   static void commit(CodeBlob* cb);                        // called when the allocated CodeBlob has been filled
 149   static int  alignment_unit();                            // guaranteed alignment of all CodeBlobs
 150   static int  alignment_offset();                          // guaranteed offset of first CodeBlob byte within alignment unit (i.e., allocation header)
 151   static void free(CodeBlob* cb);                          // frees a CodeBlob
 152   static void free_unused_tail(CodeBlob* cb, size_t used); // frees the unused tail of a CodeBlob (only used by TemplateInterpreter::initialize())
 153   static bool contains(void *p);                           // returns whether p is included
 154   static bool contains(nmethod* nm);                       // returns whether nm is included
 155   static void blobs_do(void f(CodeBlob* cb));              // iterates over all CodeBlobs
 156   static void blobs_do(CodeBlobClosure* f);                // iterates over all CodeBlobs
 157   static void nmethods_do(void f(nmethod* nm));            // iterates over all nmethods
 158   static void metadata_do(void f(Metadata* m));            // iterates over metadata in alive nmethods
 159 
 160   // Lookup
 161   static CodeBlob* find_blob(void* start);              // Returns the CodeBlob containing the given address
 162   static CodeBlob* find_blob_unsafe(void* start);       // Same as find_blob but does not fail if looking up a zombie method
 163   static nmethod*  find_nmethod(void* start);           // Returns the nmethod containing the given address
 164   static CompiledMethod* find_compiled(void* start);
 165 
 166   static int       blob_count();                        // Returns the total number of CodeBlobs in the cache
 167   static int       blob_count(int code_blob_type);
 168   static int       adapter_count();                     // Returns the total number of Adapters in the cache
 169   static int       adapter_count(int code_blob_type);
 170   static int       nmethod_count();                     // Returns the total number of nmethods in the cache
 171   static int       nmethod_count(int code_blob_type);
 172 
 173   // GC support
 174   static void gc_epilogue();
 175   static void gc_prologue();
 176   static void verify_oops();
 177   // If any oops are not marked this method unloads (i.e., breaks root links
 178   // to) any unmarked codeBlobs in the cache.  Sets "marked_for_unloading"
 179   // to "true" iff some code got unloaded.
 180   // "unloading_occurred" controls whether metadata should be cleaned because of class unloading.
 181   class UnloadingScope: StackObj {
 182     ClosureIsUnloadingBehaviour _is_unloading_behaviour;
 183 
 184   public:
 185     UnloadingScope(BoolObjectClosure* is_alive)
 186       : _is_unloading_behaviour(is_alive)
 187     {
 188       IsUnloadingBehaviour::set_current(&_is_unloading_behaviour);
 189       increment_unloading_cycle();
 190     }
 191 
 192     ~UnloadingScope() {
 193       IsUnloadingBehaviour::set_current(NULL);
 194     }
 195   };
 196   static void do_unloading(BoolObjectClosure* is_alive, bool unloading_occurred);
 197   static uint8_t unloading_cycle() { return _unloading_cycle; }
 198   static void increment_unloading_cycle();
 199   static void asserted_non_scavengable_nmethods_do(CodeBlobClosure* f = NULL) PRODUCT_RETURN;
 200   static void release_exception_cache(ExceptionCache* entry);
 201   static void purge_exception_caches();
 202 
 203   // Apply f to every live code blob in scavengable nmethods. Prune nmethods
 204   // from the list of scavengable nmethods if f->fix_relocations() and a nmethod
 205   // no longer has scavengable oops.  If f->fix_relocations(), then f must copy
 206   // objects to their new location immediately to avoid fixing nmethods on the
 207   // basis of the old object locations.
 208   static void scavenge_root_nmethods_do(CodeBlobToOopClosure* f);
 209 
 210   static nmethod* scavenge_root_nmethods()            { return _scavenge_root_nmethods; }
 211   // register_scavenge_root_nmethod() conditionally adds the nmethod to the list
 212   // if it is not already on the list and has a scavengeable root
 213   static void register_scavenge_root_nmethod(nmethod* nm);
 214   static void verify_scavenge_root_nmethod(nmethod* nm);
 215   static void add_scavenge_root_nmethod(nmethod* nm);
 216   static void drop_scavenge_root_nmethod(nmethod* nm);
 217 
 218   // Printing/debugging
 219   static void print();                           // prints summary
 220   static void print_internals();
 221   static void print_memory_overhead();
 222   static void verify();                          // verifies the code cache
 223   static void print_trace(const char* event, CodeBlob* cb, int size = 0) PRODUCT_RETURN;
 224   static void print_summary(outputStream* st, bool detailed = true); // Prints a summary of the code cache usage
 225   static void log_state(outputStream* st);
 226   static const char* get_code_heap_name(int code_blob_type)  { return (heap_available(code_blob_type) ? get_code_heap(code_blob_type)->name() : "Unused"); }
 227   static void report_codemem_full(int code_blob_type, bool print);
 228 
 229   // Dcmd (Diagnostic commands)
 230   static void print_codelist(outputStream* st);
 231   static void print_layout(outputStream* st);
 232 
 233   // The full limits of the codeCache
 234   static address low_bound()                          { return _low_bound; }
 235   static address low_bound(int code_blob_type);
 236   static address high_bound()                         { return _high_bound; }
 237   static address high_bound(int code_blob_type);
 238 
 239   // Have to use far call instructions to call this pc.
 240   static bool is_far_target(address pc);
 241 
 242   // Profiling
 243   static size_t capacity();
 244   static size_t unallocated_capacity(int code_blob_type);
 245   static size_t unallocated_capacity();
 246   static size_t max_capacity();
 247 
 248   static double reverse_free_ratio(int code_blob_type);
 249 
 250   static void clear_inline_caches();                  // clear all inline caches
 251   static void cleanup_inline_caches();                // clean unloaded/zombie nmethods from inline caches
 252 
 253   // Returns true if an own CodeHeap for the given CodeBlobType is available
 254   static bool heap_available(int code_blob_type);
 255 
 256   // Returns the CodeBlobType for the given CompiledMethod
 257   static int get_code_blob_type(CompiledMethod* cm) {
 258     return get_code_heap(cm)->code_blob_type();
 259   }
 260 
 261   static bool code_blob_type_accepts_compiled(int type) {
 262     bool result = type == CodeBlobType::All || type <= CodeBlobType::MethodProfiled;
 263     AOT_ONLY( result = result || type == CodeBlobType::AOT; )
 264     return result;
 265   }
 266 
 267   static bool code_blob_type_accepts_nmethod(int type) {
 268     return type == CodeBlobType::All || type <= CodeBlobType::MethodProfiled;
 269   }
 270 
 271   static bool code_blob_type_accepts_allocable(int type) {
 272     return type <= CodeBlobType::All;
 273   }
 274 
 275 
 276   // Returns the CodeBlobType for the given compilation level
 277   static int get_code_blob_type(int comp_level) {
 278     if (comp_level == CompLevel_none ||
 279         comp_level == CompLevel_simple ||
 280         comp_level == CompLevel_full_optimization) {
 281       // Non profiled methods
 282       return CodeBlobType::MethodNonProfiled;
 283     } else if (comp_level == CompLevel_limited_profile ||
 284                comp_level == CompLevel_full_profile) {
 285       // Profiled methods
 286       return CodeBlobType::MethodProfiled;
 287     }
 288     ShouldNotReachHere();
 289     return 0;
 290   }
 291 
 292   static void verify_clean_inline_caches();
 293   static void verify_icholder_relocations();
 294 
 295   // Deoptimization
 296  private:
 297   static int  mark_for_deoptimization(KlassDepChange& changes);
 298 #ifdef HOTSWAP
 299   static int  mark_for_evol_deoptimization(InstanceKlass* dependee);
 300 #endif // HOTSWAP
 301 
 302  public:
 303   static void mark_all_nmethods_for_deoptimization();
 304   static int  mark_for_deoptimization(Method* dependee);
 305   static void make_marked_nmethods_not_entrant();
 306 
 307   // Flushing and deoptimization
 308   static void flush_dependents_on(InstanceKlass* dependee);
 309 #ifdef HOTSWAP
 310   // Flushing and deoptimization in case of evolution
 311   static void flush_evol_dependents_on(InstanceKlass* dependee);
 312 #endif // HOTSWAP
 313   // Support for fullspeed debugging
 314   static void flush_dependents_on_method(const methodHandle& dependee);
 315 
 316   // tells how many nmethods have dependencies
 317   static int number_of_nmethods_with_dependencies();
 318 
 319   static int get_codemem_full_count(int code_blob_type) {
 320     CodeHeap* heap = get_code_heap(code_blob_type);
 321     return (heap != NULL) ? heap->full_count() : 0;
 322   }
 323 
 324   // CodeHeap State Analytics.
 325   // interface methods for CodeHeap printing, called by CompileBroker
 326   static void aggregate(outputStream *out, const char* granularity);
 327   static void discard(outputStream *out);
 328   static void print_usedSpace(outputStream *out);
 329   static void print_freeSpace(outputStream *out);
 330   static void print_count(outputStream *out);
 331   static void print_space(outputStream *out);
 332   static void print_age(outputStream *out);
 333   static void print_names(outputStream *out);
 334 };
 335 
 336 
 337 // Iterator to iterate over nmethods in the CodeCache.
 338 template <class T, class Filter> class CodeBlobIterator : public StackObj {
 339  public:
 340   enum LivenessFilter { all_blobs, only_alive, only_alive_and_not_unloading };
 341 
 342  private:
 343   CodeBlob* _code_blob;   // Current CodeBlob
 344   GrowableArrayIterator<CodeHeap*> _heap;
 345   GrowableArrayIterator<CodeHeap*> _end;
 346   bool _only_alive;
 347   bool _only_not_unloading;
 348 
 349  public:
 350   CodeBlobIterator(LivenessFilter filter, T* nm = NULL)
 351     : _only_alive(filter == only_alive || filter == only_alive_and_not_unloading),
 352       _only_not_unloading(filter == only_alive_and_not_unloading)
 353   {
 354     if (Filter::heaps() == NULL) {
 355       return;
 356     }
 357     _heap = Filter::heaps()->begin();
 358     _end = Filter::heaps()->end();
 359     // If set to NULL, initialized by first call to next()
 360     _code_blob = (CodeBlob*)nm;
 361     if (nm != NULL) {
 362       while(!(*_heap)->contains_blob(_code_blob)) {
 363         ++_heap;
 364       }
 365       assert((*_heap)->contains_blob(_code_blob), "match not found");
 366     }
 367   }
 368 
 369   // Advance iterator to next blob
 370   bool next() {
 371     assert_locked_or_safepoint(CodeCache_lock);
 372 
 373     for (;;) {
 374       // Walk through heaps as required
 375       if (!next_blob()) {
 376         if (_heap == _end) {
 377           return false;
 378         }
 379         ++_heap;
 380         continue;
 381       }
 382 
 383       // Filter is_alive as required
 384       if (_only_alive && !_code_blob->is_alive()) {
 385         continue;
 386       }
 387 
 388       // Filter is_unloading as required
 389       if (_only_not_unloading) {
 390         CompiledMethod* cm = _code_blob->as_compiled_method_or_null();
 391         if (cm != NULL && cm->is_unloading()) {
 392           continue;
 393         }
 394       }
 395 
 396       return true;
 397     }
 398   }
 399 
 400   bool end()  const { return _code_blob == NULL; }
 401   T* method() const { return (T*)_code_blob; }
 402 
 403 private:
 404 
 405   // Advance iterator to the next blob in the current code heap
 406   bool next_blob() {
 407     if (_heap == _end) {
 408       return false;
 409     }
 410     CodeHeap *heap = *_heap;
 411     // Get first method CodeBlob
 412     if (_code_blob == NULL) {
 413       _code_blob = CodeCache::first_blob(heap);
 414       if (_code_blob == NULL) {
 415         return false;
 416       } else if (Filter::apply(_code_blob)) {
 417         return true;
 418       }
 419     }
 420     // Search for next method CodeBlob
 421     _code_blob = CodeCache::next_blob(heap, _code_blob);
 422     while (_code_blob != NULL && !Filter::apply(_code_blob)) {
 423       _code_blob = CodeCache::next_blob(heap, _code_blob);
 424     }
 425     return _code_blob != NULL;
 426   }
 427 };
 428 
 429 
 430 struct CompiledMethodFilter {
 431   static bool apply(CodeBlob* cb) { return cb->is_compiled(); }
 432   static const GrowableArray<CodeHeap*>* heaps() { return CodeCache::compiled_heaps(); }
 433 };
 434 
 435 
 436 struct NMethodFilter {
 437   static bool apply(CodeBlob* cb) { return cb->is_nmethod(); }
 438   static const GrowableArray<CodeHeap*>* heaps() { return CodeCache::nmethod_heaps(); }
 439 };
 440 
 441 typedef CodeBlobIterator<CompiledMethod, CompiledMethodFilter> CompiledMethodIterator;
 442 typedef CodeBlobIterator<nmethod, NMethodFilter> NMethodIterator;
 443 
 444 #endif // SHARE_VM_CODE_CODECACHE_HPP